Abstract P440: Antagonism of Thromboxane-Prostanoid Receptor Attenuates Alcohol-Induced Myocardial Inflammation

Abstract

Heavy alcohol use is the leading etiology of non-ischemic dilated cardiomyopathy. Alcohol-Associated Cardiomyopathy (ACM) is a specific cardiac muscle disease which is characterized by inflammation, abnormal fatty acid metabolism, and oxidative stress. TP-R, a G-protein coupled receptor, is widely expressed in the myocardium, and plays a critical role in the pathogenesis of various cardiac diseases including hypertensive heart disease and dilated cardiomyopathy. TP-R is activated by thromboxane A2 (TXA2) and 8-isoprostane. Of note, clinical studies have shown that chronic alcohol use markedly increases the level of thromboxane B2, a stable metabolite of TXA2, in plasma of alcohol use disorder patients. However, the role of TP-R signaling in the pathogenesis of ACM remains unclear. Therefore, we hypothesize that TP-R signaling mediates adverse effects of alcohol on the myocardium. To test this hypothesis, we used the chronic plus binge ethanol feeding model. C57BL/6 wild-type male mice (8-week) were fed with Lieber-Decarli ethanol (5% v/v) diet (ET, n = 10) or isocaloric control diet (CON, n = 6) for ten days followed by single binge of ethanol or maltose-dextrin via oral gavage. A cohort of ethanol-fed mice received SQ 29,548, a TP-R antagonist (ET+SQ, n = 8). Our data indicated that mouse myocardial protein levels of thromboxane A2 synthase (TBXAS1, P <0.001), an enzyme responsible for synthesis of TXA2, was increased in response to ethanol exposure. Concomitantly, ethanol-fed mice displayed upregulated myocardial protein levels of pro-inflammatory mediators including tumor necrosis factor alpha (TNF-α, P <0.001) and secreted interleukin 1 beta (IL1β, P <0.001) compared with their controls. These adverse alterations induced by the ethanol diet were ameliorated by the pharmacological inhibition of TP-R. Interestingly, RNA-sequencing and western blotting analysis showed that expression of thioredoxin-interacting protein (TXNIP) was upregulated in response to ethanol exposure ( P <0.001). Meanwhile, mice fed with ethanol diet had the increased myocardial protein level of NLR family pyrin domain containing 3 (NLRP3, P <0.01) compared with CON mice. These ethanol-induced increases in protein levels of TXNIP ( P <0.001) and NLRP3 ( P <0.01) were attenuated due to SQ 29,548 administration. Accordingly, these findings lead us to suggest that pharmaceutical inhibiting TP-R has protective effects on attenuating ethanol-induced myocardial inflammation by inhibiting TXNIP-NLRP3-IL1β axis.